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Vitamin D may lower blood pressure

March 27, 2013

A new US study reports that regular vitamin D supplementation may help African-Americans lower their blood pressure.

In the randomized controlled trial, 250 African-American adults were divided into four groups: three of the groups received daily vitamin D supplementation of 1000, 2000, or 4000 IU for three months, while the fourth group received a placebo (1). The study results showed that the participants in the supplementation group had a decrease in systolic blood pressure by an average of 0.7 to 4 mm Hg, with those who received the highest vitamin D dose benefiting the most. Participants in the placebo group showed a rise in systolic blood pressure (1.7 mm Hg).

The researchers commented that the blood pressure lowering effects of vitamin D were modest but signifi-cant. If further research should be found support these findings, widespread use of vitamin D supplemen-tation among African-Americans could have significant public health benefits. High blood pressure, a risk factor for heart attacks, heart failure and stroke, is 40 percent more common in African-Americans than in other American ethnic groups.

Numerous observational studies have implicated vitamin D insufficiency and deficiency as risk factors for hypertension, cardiovascular disease and kidney disease. Results of randomized controlled trials investiga-ting beneficial effects of vitamin D supplementation have been inconclusive so far (2). Several putative mechanisms underlying the potential vascular and renal effects of vitamin D have been discussed: low vitamin D levels seem to be associated with increased activation of the renin-angiotensin-system (RAS), contributing directly to elevations in blood pressure as well as to renal injury. On the other hand, higher blood vitamin D concentrations have been linked to improved endothelial function, reduced oxidative stress and inflammation.